Help me rebuild my Bent

[Joe.B]

I went through the same ‘bent or upwrong’ conundrum as Blodwyn Pig, (see ‘I’ve come to a conclusion’ topic), few years ago and ended up striping down my Challenge Sieran and donating its components to a Surly LHT in a quest for greater versatility.

At various times during the 5 years or so since then I considered rebuilding it but now that Mrs.B is back on a recumbent, (used Scorpion from Kinetics), I really think I might get it running again.

I’ve already started thinking about how I’d rebuild it. Previously it had a Rohloff/Schmitt Dyno 559 size wheels and BB7’s. More recently it’s been on loan to the good Mr Aidan.f of this parish, he ran it set up for BHPC races with 700x25, (no room for mudguards with those), calliper brakes and high, narrow gearing. Although it’s still in Aidan’s configuration for the rides and local roads I’ll be riding I think I’d prefer 26x1.5, disc brakes and some wide gear ratios.   

It won’t be getting the Rohloff/Dyno wheels back as they will remain on the Trucker, reasonable quality 559 are plentiful on fleabay so no problem there. Brakes, if I can afford it will be Magura hydraulics, otherwise BB7’s from my box of odd bits.

It’s the gearing that I’m really not sure about:
Twist shifters work well on tiller steered recumbents and in the past I've had good results with SRAM X5/7 setups. These days though options for twist shifters aren’t so good so maybe bar-end shifters mounted on handlebar adapters? (Might have some 9spd bar ends in the afore mentioned box).

I’m really not up to date at all with the current state of play with derailleur/shifter compatibility. Likewise whether modern 10/11 speed derailleurs work when used with 9 speed chains & shifters?

BTW I’ve been a bit absent from this place over the last year or so, life, family, work and all that. Though mostly because my work IT allowed me to view YACF but not log in, and I can’t stand typing more than 12 sequential words on my phone. YACF now seems to be miraculously unblocked at work so hurrah, praise be the IT bods, peace be upon them and all that.       

[McWheels]

Is this for a quick bike, a working/hack bike, a commuter, touring? My instinct is to try and go IGH until proven unsuitable, and yes aren't Rohloff's expensive? But Shimano and Sturmey-Archer both do 8-ish-sp options. I ran the SA 8-Sp for a few years and sold that bike with it still installed - the chain line was exquisite and I rather liked the companionship of the different fizzing and whirring sounds of each gear.

Current bike came with a bar-end-shifted Shimano 1x10 and it's pretty good too, and faster. But it's not a way to cross types and speeds. Deeper parts of the internet may know more than me.

[cycleman]

Low gears on a recumbent being quite important I would say the only igh suitable would be either rolloff or pinion. Shimano hubs don't have enough gear range for more than utility riding in my experience 

[LittleWheelsandBig]

Shimano’s 11sp hub is about 400%, their 8sp is around 300% and Rohloff just over 500%. A 400% range is marginal for touring, requiring a small compromise at the low end and a big compromise at the high end i.e. normal cruising gear being the second-highest. A 300% range isn’t worthwhile for touring unless you are a masochist.

[Joe.B]

To some extent I’ve stalled a little bit with this project, just too much going on and lots of outdoor work to get finished while the weather allows.

I have had the bike running lovely with an old Sora 9sp mech, at least until low gears were required. At that point I encountered so much chain skipping it was imposable to keep climbing. It didn’t take long to pin that problem down to a B-screw adjustment issue so a new Alivio 9sp derailleur was fitted.

With the 9sp Alivio I’m finding that when selecting a gear in the bottom half of the cassette the chain is coming off the bottom jockey wheel and running between the jockey wheel and cage.

There is quite a bit of chainline misalignment between the return chain idler and the cassette but that isn’t unusual on a bent. I think I will remove the Deore 9sp mech currently fitted to our Circe Helios and see if that is any better.     

With regard the IGH’s; the Rolhoff that was originally on the Seiran has been fitted to my Surly LHT since 2018. I could always swap it back over and run the Surly with the 9 speed setup currently on the bent.

[Joe.B]

To some extent I’ve stalled a little bit with this project, just too much going on and lots of outdoor work to get finished while the weather allows.

I have had the bike running lovely with an old Sora 9sp mech, at least until low gears were required. At that point I encountered so much chain skipping it was imposable to keep climbing. It didn’t take long to pin that problem down to a B-screw adjustment issue so a new Alivio 9sp derailleur was fitted.

With the 9sp Alivio I’m finding that when selecting a gear in the bottom half of the cassette the chain is coming off the bottom jockey wheel and running between the jockey wheel and cage.

There is quite a bit of chainline misalignment between the return chain idler and the cassette but that isn’t unusual on a bent. I think I will remove the Deore 9sp mech currently fitted to our Circe Helios and see if that is any better.     

With regard the IGH’s; the Rolhoff that was originally on the Seiran has been fitted to my Surly LHT since 2018. I could always swap it back over and run the Surly with the 9 speed setup currently on the bent.

Just occurred to me that I could share the Rolhoff wheel between the two bikes, (can’t ride then both at the same time).  I’d just need another twist shifter and shifter box.